Organic Film Electrode Connection for PCB Cost Reduction

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Solution Overview

Problem

The complex production process and increased cost associated with gold plating in establishing electrical connections using anisotropic conductive adhesives for electronic devices, particularly in miniaturized components, necessitate a simpler and cost-effective method for forming connections between printed circuit boards and electronic components.

Innovation Solution

The use of organic solderability preservation (OSP) treatment to form an organic film instead of gold plating, which is then removed or thinned to ensure direct contact between electrodes and conductive particles, allowing for effective electrical conduction without the need for expensive gold plating, using either anisotropic or non-conductive adhesives with electrically conductive particles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If gold plating is applied to electrodes for connection using adhesive, then oxidation prevention and electrical conduction properties are improved, but production process complexity and cost increase

Engineering Contradiction:
Improveoxidation prevention and electrical conduction propertiesVSAvoidproduction process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces expensive gold plating with a cheaper organic film (OSP treatment) that serves the same oxidation prevention function. The organic film is applied as a temporary protective layer during manufacturing and is removed before final assembly, eliminating the need for costly gold plating while maintaining reliability during the production process.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent extracts the essential function of gold plating (oxidation prevention) and separates it from the costly material aspect. By using OSP treatment, the oxidation prevention function is achieved without the expensive gold layer, and the organic film is subsequently removed, leaving the electrode ready for adhesive bonding without requiring gold plating.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If gold plating is applied to electrodes for connection using adhesive, then electrical conduction properties are improved, but production cost increases

Engineering Contradiction:
Improveelectrical conduction propertiesVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent uses a disposable organic film (OSP treatment) that is much cheaper than gold plating. This organic film provides the necessary oxidation prevention and electrical conduction properties during manufacturing, then is removed before final assembly, eliminating the need to bear the high cost of gold plating while maintaining adequate electrical performance.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent creates a functional copy of gold plating using OSP treatment. The organic film replicates the oxidation prevention and electrical conduction properties of gold plating at a fraction of the cost, serving as a cost-effective alternative that achieves the same functional objectives without the high material and process costs associated with gold.

Inventive Principle:
Principle #26Copying

3Ease of manufacture

If organic film is formed on electrodes for connection using adhesive, then production process is simplified and cost is reduced, but direct contact between electrodes and conductive particles may be inhibited

Engineering Contradiction:
Improveproduction process simplicity and costVSAvoiddirect contact between electrodes and conductive particles
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies OSP treatment as a preliminary action during the manufacturing process to protect electrodes and simplify production. The organic film is formed on electrodes before assembly, providing oxidation prevention and cost reduction. Before final assembly, the organic film is removed from areas requiring direct contact, ensuring that conductive particles can make proper contact with electrodes without interference from the organic film.

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach simplifies the production process, reduces material costs, and ensures reliable electrical connections by ensuring that electrodes and conductive particles make direct contact, inhibiting defective conduction and maintaining low resistance across varying organic film thicknesses.

Implementation Method 1

form an organic film by OSP treatment... leads to a simple production process

Methodology Applied
Scientific EffectOxidation prevention: Oxidation

Implementation Method 2

treatment to remove or thin the organic film is treatment to bring the organic film into contact with an acidic solution or its vapor

Methodology Applied
Scientific EffectChemical etching: Chemical Bonding

Implementation Method 3

some of the electrically conductive particles are arranged between the connection electrode and the electrode for connection using an adhesive, thereby establishing an electrical connection

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 4

the heating and pressurization allow a resin in the adhesive to flow to seal a gap between an electrode for connection using an adhesive formed on a surface of a printed circuit board and a connection electrode formed on an interconnection substrate

Methodology Applied
Scientific EffectThermal softening: Melting

Data Source

PatentEP2440024B1Connection method
Publication Date: 2014.03.12 SUMITOMO ELECTRIC INDUSTRIES LTD
  • EP2440024B1 patent drawingFigure 1
  • EP2440024B1 patent drawingFigure 2
  • EP2440024B1 patent drawingFigure 3

AI summary

[Object] Provided are a connection method and an electronic device, in which the manufacturing process can be simplified, and a connection structure using an adhesive can be produced at low cost. [Solution] A connection method according to the present invention includes a step (a1) of preparing base materials 10 and 21 each including an electrode for connection using an adhesive, a step (b1) of covering electrodes 12 and 22 for connection using an adhesive with organic films 15 configured to prevent oxidation, the electrodes 12 and 22 being located on the base materials, a step (c1) of removing or thinning the organic films, and after the step (c1), a step (d1) of bonding the electrodes for connection using an adhesive to each other with an adhesive 30 mainly containing a thermosetting resin to establish electrical connection.